1. Field of the Invention
The present invention relates to a method for manufacturing an electronic component. In more detail, the present invention relates to an electronic component with a shield case for housing surface mounting components mounted on a substrate.
2. Description of the Related Art
Electronic components comprises an electronic component 60 with a shield case 65 for housing surface mounting components 64 as shown in FIG. 17. The method for manufacturing the electronic component with such shield case includes the following procedures.
(1) Through-holes 62 are formed on a substrate (a mother substrate) 61 provided with a plurality of substrates 51 for mounting the components, and a shield case attachment electrode 63 is formed on an inner circumference face (side face) of each through hole 62 as shown in FIG. 18.
(2) In the next step, the surface mounting components 64 are mounted on a sheet substrate (the mother substrate) 61, and the surface mounting components 64 are soldered to land electrodes (not shown) of the sheet substrate 61.
(3) Subsequently, a solder paste 67 is filled in the through hole 62.
(4) Then, each engaging pin 66 of a plurality of the shield cases 65 is inserted into the respective through hole 62 filled with the solder paste 67.
(5) Then, a plurality of the shield cases 65 are soldered to the substrate 61 by allowing the solder in the solder paste 67 to melt. The shield cases 65 are connected and fixed to the substrate 61 as shown in FIG. 17 by soldering the engaging pin 66 to the fixing electrodes (shield case attachment electrodes) 63 in the through holes 62.
(6) Finally, an individual electronic component 60 as shown in FIG. 17 is obtained by cutting the sheet substrate 61 along the lines (cutting lines) Axe2x80x94A using a dicing machine.
However, the shield case has been soldered by inserting the engaging pins 66 of the shield case 65 into the through holes 62 after filling the through hole 62 with the solder paste 67. Since the shield case is fixed by almost completely filling the solder in the through holes 62, the solder layer is cut when the mother substrate is cut (diced) into pieces. As a result, it has been a problem that the planarity of the product is compromised due to flashes of the solder, product characteristics are deteriorated by adhesion of solder debris to the product, and cutting becomes insufficient due to loading of the solder on the cutting blade.
In addition, special solder filling equipment is needed for filling the solder paste 67 into the through hole 62, and the amount of the consumed solder paste is increased, raising material cost.
Accordingly, the object of the present invention for solving the problems as hitherto described is to provide a method for enabling an electronic component with a shield case housing surface mounting components mounted on a substrate to be manufactured by eliminating the step for filling the solder paste into the engaging hole, a highly reliable electronic component with a shield case manufactured by the method described above.
According to the present invention, a method for manufacturing an electronic component with a shield case for housing surface mounting components mounted on a substrate, comprising the steps of: pre-treating for soldering by inserting engaging pins of the shield case into engaging holes of a mother substrate provided with a plurality of the engaging holes, case fixing electrodes for attaching a plurality of the shield cases are disposed on the inner surfaces of the engaging holes, while applying a solder paste on the circumference of the engaging holes, or on an area including the periphery of engaging holes and at least a part of each engaging holes, on an opposite surface to the component mounting surface covered with the shield case on the mother substrate; placing the mother substrate on which the shield case is mounted in a reflow furnace and soldering and fixing each engaging pin of the shield case to the case fixing electrode by reflow soldering; and cutting the mother substrate, on which each engaging pin of the shield case is soldered to respective case fixing electrodes, into respective areas on which each shield case is mounted to divide the mother substrate into individual electronic component with the shield case housing the surface mounting components.
The engaging pin of the shield case is inserted into the engaging hole of the mother substrate, and the engaging pin is soldered to the engaging hole by reflow soldering while the solder paste is coated on the circumference, as well as on the area including the circumference of the engaging hole and at least a part of the engaging hole, at the reverse face (the back face) to the component mounting face covered with the shield case on the mother substrate. Consequently, the molten solder reaches the inside of the engaging hole and permeates into the gap between the engaging pin of the shield case and the case fixing electrode in the engaging hole to connect and fix the engaging pin to the case fixing electrode with the solder. Accordingly, the shield case is securely attached to the substrate (the mother substrate) without requiring the solder paste to be filled in the engaging hole.
Since the solder is not filled in the engaging hole, but a little amount of the solder permeates into the engaging hole, the solder is seldom cut in the cutting step of the mother substrate. Therefore, troubles such as deterioration of flatness of the product due to burrs of the solder caused by cutting the solder, deterioration of characteristics of the product due to adhesion of solder debris to the product, and insufficient cutting due to loading of the solder on the cutting blade can be suppressed and prevented.
The phrase xe2x80x9ccoating a solder paste on the circumference of the engaging hole, or on the area including the periphery of each engaging hole and at least a part of each engaging holexe2x80x9d as used in the present invention is a concept meaning that the solder paste is coated either only on the circumference of the engaging hole, or the solder paste is coated not only the circumference of the solder paste, but is also coated on the area including (covering) at least a part of the engaging hole in plane view. The method for coating the solder paste is not particularly limited in the present invention, but various method such as screen printing method, or a method for coating in a given pattern using a metal mask can be used.
Preferably, the inner side surface of the engaging pin comes into close contact with the inner circumference face of the engaging hole of the mother substrate when the engaging pin is inserted into the engaging hole on the mother substrate.
The inner side face of the engaging pin comes into close contact with the inner circumference face of the engaging hole of the mother substrate when the engaging pin is inserted into the engaging hole on the mother substrate. Therefore, the molten solder is easily permeate into the gap, because of capillary phenomena, between the inner circumference face of the engaging pin and the case fixing electrode, thereby reliability of attachment of the case is improved.
Preferably, the step for pre-treatment for soldering comprises: (a) coating the solder paste on a connection land electrode to which the surface mounting components mounted on the component mounting surface of the mother substrate is electrically and mechanically connected; (b) coating the solder paste on the circumference of the engaging hole, or on the area including the periphery of the engaging hole and at least a part of the engaging hole, on the opposite surface of the mother substrate; (c) mounting the surface mounting component on the connection land electrode via the solder paste coated on the component mounting surface of the mother substrate; and (d) mounting the shield case on the mother substrate by inserting each engaging pins of the shield case into respective engaging holes, wherein the surface mounting component is soldered to the connection land electrode at the same time when the engaging pin of the shield case is soldered to the case fixing electrode by the reflow soldering in the soldering step.
As described above, the solder paste is coated on the connection land electrode, and is also coated on the circumference of the engaging hole as well as on the area including the circumference of the engaging hole and at least a part of the engaging hole at the back face of the mother substrate, and the engaging pin of the shield case is inserted into the engaging hole after mounting the surface mounting component on the connection land electrode via the solder paste for the pre-treatment for soldering. As a result, the surface mounting component can be soldered on the connection land electrode at the same time when the engaging pin of the shield case is soldered on the case fixing electrode by reflow soldering in the soldering step. Accordingly, only one time of reflow soldering may be sufficient to simplify the manufacturing process, while the number of heating cycle may be reduced to enable deterioration of the surface mounting component to be prevented.
Preferably, the step for pre-treatment for soldering comprises: (a) coating the solder paste on a connection land electrode to which the surface mounting components mounted on the component mounting surface of the mother substrate is electrically and mechanically connected; (b) mounting the surface mounting component on the connection land electrode via the solder paste coated on the component mounting surface of the mother substrate; (c) mounting the shield case on the mother substrate by inserting the engaging pin into the engaging hole; and (d) coating the solder paste on the circumference of the engaging hole, or on the area including the periphery of the engaging hole and at least a part of the engaging hole, on the opposite surface of the mother substrate; wherein the surface mounting component is soldered to the connection land electrode at the same time when the engaging pin of the shield case is soldered to the case fixing electrode by the reflow soldering in the soldering step.
The solder paste is coated on the connection land electrode, is also coated on the circumference of the engaging hole, or on the area including the circumference of the engaging hole and at least a part of the engaging hole, at the back face of the mother substrate after mounting the surface mounting component on the connection land electrode via the solder paste, and the engaging pin is inserted into the engaging hole for the pre-treatment for soldering. As a result, the surface mounting component can be also soldered on the connection land electrode at the same time when the engaging pin of the shield case is soldered on the case fixing electrode by reflow soldering in the soldering step. Accordingly, only one time of reflow soldering may be sufficient to simplify the manufacturing process, while the number of heating cycle may be reduced to enable deterioration of the surface mounting component to be prevented.
Preferably, the step for pre-treatment for soldering comprises: (a) inserting the engaging pin into the engaging hole of the mother substrate on which the surface mounting component is soldered to the connection land electrode of the component mounting surface; and (b) coating the solder paste on the circumference of the engaging hole, or on the area including the periphery of the engaging hole and at least a part of the engaging hole, on the opposite surface of the mother substrate; wherein the engaging pin of the shield case is soldered to the case fixing electrode by reflow soldering in the soldering step.
The engaging pin of the shield case is inserted into the engaging hole of the mother substrate in which the surface mounting component is soldered to the connection land electrode on the component mounting face, and the solder paste is coated on the circumference of the engaging hole as well as on the area including the circumference of the engaging hole and at least on a part of the engaging hole for the pre-treatment for soldering. In this case, the engaging pin of the shield case is soldered to the case fixing electrode in the soldering step.
In other words, it is possible in the present invention to solder the engaging pin of the shield case to the case fixing electrode in a different step from the step for as soldering the surface mounting component to the connection land electrode. The process may be applied when an another step should be inserted between the step of mounting the surface mounting component and the step of soldering engaging pin of the shield case to the case fixing electrode, or when soldering of the surface mounting component to the connection land electrode can not be simultaneously applied with soldering of the engaging pin of the shield case to the case fixing electrode for the convenience of forming the metal mask for printing. In this case, the shield case can be also efficiently and securely attached without requiring the step for filling the paste into the engaging hole.
Preferably, according to the electronic component with a shield case produced by the above manufacturing method, the surface mounting component is soldered to the connection land electrode on the substrate, and the engaging pin of the shield case is soldered to the case fixing electrode disposed on the inner circumference face of the engaging hole of the substrate from the back surface of the substrate.
Since the electronic component with a shield case comprises the structure in which the surface mounting component is soldered to the connection land electrode on the substrate, and the engaging pin of the shield case in which the surface mounting component is housed is soldered to the case fixing electrode disposed on the inner circumference face of the engaging hole of the substrate from the back face side of the substrate, the shield case is securely attached to the substrate with high reliability.